AutoCodes – GMC – P1338 2016 GMC Sierra

P1338 2016 GMC Sierra Code - Cylinder 1 Glow Plug Offset Exceeded Learning Limit

Quick Answer

The Glow Plug Control Module has not learned the glow plug offset values. Common causes include Perform Glow Plug Learn procedure, Faulty Glow Plug 1, Glow Plug 1 harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1338 2016 GMC Sierra indicates Cylinder 1 Glow Plug Offset Exceeded Learning Limit.
Common causes: Common causes include Perform Glow Plug Learn procedure, Faulty Glow Plug 1, Glow Plug 1 harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 237

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 30, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P1338 2016 GMC Sierra Description

The Glow Plug Control Module has not learned the glow plug offset values. If a glow plug has been replaced and the glow plug learn was not performed, or if the Glow Plug Control Module experiences an Electronically Erasable Programmable Read Only Memory (EEPROM) error or data corruption, this Diagnostic Trouble Code (DTC) to set. The DTC will be set if the glow plug hot resistance is outside a predefined threshold.

OBDII Code P1338 2016 GMC Sierra - Cylinder 1 Glow Plug Offset Exceeded Learning Limit - AutoCodes.com — P1338 2016 GMC Sierra Code - Cylinder 1 Glow Plug Offset Exceeded Learning Limit

What does this mean?

What are the Possible Causes of the DTC P1338 2016 GMC Sierra?

Perform Glow Plug Learn procedure
Faulty Glow Plug 1
Glow Plug 1 harness is open or shorted
Glow Plug 1 circuit poor electrical connection

How to Fix the DTC P1338 2016 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

If a Glow Plug was replaced, perform a Glow Plug Learn procedure with a Scan Tool.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1338 2016 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P1338 2016 GMC Sierra code?

Need more information on how to fix the P1338 2016 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1338 2016 GMC Sierra Code

What does the OBDII code P1338 mean for a 2016 GMC Sierra?

P1338 indicates that the Cylinder 1 Glow Plug Offset has exceeded its learning limit, suggesting an issue with the glow plug system or related components.

What are the common symptoms of code P1338 in a 2016 GMC Sierra?

Symptoms may include difficulty starting the engine, rough idle, reduced engine performance, and the check engine light being illuminated.

What causes code P1338 in a 2016 GMC Sierra?

Common causes include a faulty glow plug in cylinder 1, a damaged glow plug control module, wiring or connector issues, or carbon buildup affecting the glow plug's performance.

How do I diagnose code P1338 on a 2016 GMC Sierra?

Start by scanning for OBDII codes, inspecting the glow plug for cylinder 1, checking the wiring and connectors for damage, and testing the glow plug control module.

Can I drive my 2016 GMC Sierra with code P1338?

Driving with this code is possible but not recommended, as it can lead to poor engine performance, starting issues, and potential damage to other components.

How is code P1338 fixed on a 2016 GMC Sierra?

Repairs may include replacing the faulty glow plug, repairing damaged wiring or connectors, cleaning carbon buildup, or replacing the glow plug control module if necessary.

What tools are needed to fix code P1338 on a 2016 GMC Sierra?

A basic OBDII scanner, multimeter, and tools for removing the glow plug and inspecting wiring are typically required for diagnosing and fixing this code.

How much does it cost to repair code P1338 on a 2016 GMC Sierra?

Repair costs vary but generally range between $100 and $300, depending on whether the glow plug, control module, or wiring needs replacement.

Can bad fuel cause code P1338 in a 2016 GMC Sierra?

Bad fuel is not a direct cause of this code, but poor fuel quality can exacerbate other issues like carbon buildup, which may contribute to glow plug problems.

How can I prevent code P1338 from occurring again in my 2016 GMC Sierra?

Regularly inspect and maintain the glow plug system, use high-quality diesel fuel, and ensure proper engine maintenance to prevent future issues.